It is a known practice to prepare beverages from pulverulent compositions based on coffee, cocoa, or the like in automatic dispensers. The process involves mixing a specified amount of a powder with a specified volume of cold or hot water to reconstitute a beverage. In general, the powder is stored "in bulk" in one or more reservoirs located in the upper part of the dispenser. The powder is collected in a hopper which is a downward extension of the reservoir and a metering device, such as a metering screw, is positioned horizontally downstream of the hopper to supply the desired amount of powder to be mixed with water on demand of the user. The powder and the water are typically mixed directly in the beverage container or in an intermediate mixing bowl. The beverage is then dispensed for consumption by the user.
This method of preparing beverages, however, has numerous drawbacks. For example, the dispensers need to be regularly supplied with the pulverulent powder which requires pouring the powder into the reservoirs by tipping a container of the powder. This method of loading is not very practical, is non-hygienic, and takes a long time to perform. In addition, in order for the device to have a sufficient service capacity, relatively large volumes of powder are held in the reservoir, which requires a relatively bulky dispensing device. A large dispensing device can be a major drawback especially when the dispenser needs to be used in tight spaces, such as when the dispensers are installed in the catering service of public transportation facilities such as aircraft, trains, and the like.
The powdered products are also highly sensitive to heat and moisture while they are in storage and lumps of product often tend to form that can lead to problems with metering and/or the dispensing device becoming blocked. Similarly, powdered compositions typically undergo oxidation quickly because the powdered or agglomerated granular product has a relatively large surface area that is in contact with ambient air. Oxidation results in a loss of flavor and freshness.
Another drawback with known dispensing devices is the production of "fines" that result when agglomerated solids, such as those based on coffee, for example, become disagglomerated. These "fines" form a dust that tends to settle out and accumulate at the bottom of the hoppers or reservoirs. The accumulation of "fines" makes metering less accurate. Regular maintenance is therefore required in order to clean the machine. This results in significant waste of raw material.
Yet another drawback with known dispensing devices results from the absence of a physical correspondence or tailoring between the powdered composition and the dispensing device, so that the powdered composition that is intend to be used in the device can be substituted for by any arbitrary type of powdered composition, which may be of inferior quality. Thus, the quality of the final product is difficult to control and the consumer can no longer be assured of obtaining a quality product.
U.S. Pat. No. 5,237,910 relates to a beverage dispenser that feeds powder or granules into a hopper from storable cartridges. The cartridges are opened by mechanical means such as knives. Such a system, however, has many of the drawbacks associated with the storage and feed of pulverulent foodstuffs in conventional dispensers.
There remains a need for improved methods of preparing and dispensing, on demand, beverages or sauces from water-dispersible foodstuffs.